1. Field of the Invention
The invention relates to the continuous extruding of a cohesive wire of a thermosetting elastomeric material at a temperature above the minimum curing temperature of the material from a particulate feed of said material in uncured form.
2. Prior Art The feeding of particulate material through a screw-type grinder/blender to form one or more wires of blended material is well known. With certain material, however, and more particularly with thermosetting elastomeric materials when it is desirable for one reason or another to extrude a cohesive wire of said elastomeric material at a temperature above the minimum curing temperature thereof, serious problems are encountered in using a common screw-type extruding apparatus. In particular, when the wire of elastomeric material to be extruded is to be extruded at a temperature above the minimum curing temperature of the particular elastomer being extruded, problems often arise of clogging within the screw-type extruder caused by premature curing of the elastomer. Such problems are met, for example, when the material being extruded comprises a copolymer of hexafluoropropylene and polyvinylidene fluoride. Yet it is highly desirable in many instances to have the wire of elastomer be at above the minimum curing temperature therefor when it is extruded so that, for example, the wire can in a continuous operation be quickly shaped as in a mold and uniformly cured into a desired shape. Further, the particulate elastomer fed into the extruding apparatus must be at, or heated within the apparatus to, a temperature high enough so that it will soften and meld into a continuous medium if a uniform cohesive wire of the elastomer is to be formed.
The present invention provides a unique and useful apparatus for the continuous extruding of a cohesive wire of a thermosetting elastomeric material at a temperature above the minimum curing temperature thereof starting with a particulate feed, and wherein clogging of the screw-type extruder portion of the apparatus is eliminated or at least minimized.